Office chair with high-technology armrest equipped with integrated control buttons for adjusting the movements of the seat and the seat back

ABSTRACT

This and other purposes are fulfilled by the present innovation, according to the characteristics of which in the annexed claims, it solves the problems indicated above by means of a high-technology armrest with integrated buttons connected to a command transmission cable for the adjustment of the seat and the seat back movements of an office chair with articulations for the synchronized movement of the seat plane and the seat back, comprising a mobile base of the “rocket launcher” type, from which base a column rises, which is adjustable in height, and which supports the seat plane and the reciprocally hinged seat back, whereby:  
     a first armrest of the office chair is equipped near the front end with two side-by-side buttons, of which a first button performs the function of releasing the movement of the seat plan and the inclination of the seat back, and a second button, adjacent to the first, activates the locking function of the seat plane and the inclination of the seat back;  
     a second armrest of the office chair, designed symmetrically to the first, which is equipped near the front end with a single-control button, for the function of adjusting the height of the chair.

RELATED U.S. APPLICATIONS

[0001] Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not applicable.

REFERENCE TO MICROFICHE APPENDIX

[0003] Not applicable.

FIELD OF THE INVENTION

[0004] The subject of the present invention is an office chair with ahigh-technology armrest equipped with integrated control buttons foradjusting the movements of the seat and the seat back, and morespecifically the inclination of the seat plane and the seat back, aswell as the height of the seating position.

[0005] The proposal finds a particular, but not exclusive, applicationin the sector of quality chairs for office furnishings.

BACKGROUND OF THE INVENTION

[0006] Adjustable office seats and chairs are certainly well-known. Toenable a more comfortable seating position than lower-priced models,which are usually fixed, they incorporate, in addition to a device foradjusting the height of the seat, the use of a device for the controlledswinging of the seat back, generally located in the part immediatelybeneath the seat plane and integral to it. This device is primarilyactivated via a protruding lever that can easily be gripped andtherefore rotated in one direction or another, until the internalmechanism releases the articulation.

[0007] In short, it is therefore possible to maintain that the followingare known:

[0008] 1. chairs in which the seat and the seat back are designed withseparate body shells, which are connected in such a way that aninclination of the seat back corresponds to a parallel downward movementof the seat plane;

[0009] 2. chairs in which only the seat back is freely swinging;

[0010] 3. chairs in which the raising of the seat plane corresponds tothe inclination of the seat back;

[0011] 4. chairs in which both the seat and the seat back areindividually adjustable;

[0012] 5. finally, seats in which both the seat plane and the seat back,which are interconnected, perform a synchronized swinging movement.

PRIOR ART

[0013] By way of an example, a first dynamic device for chairs isdescribed in FR2075176 (Suspa), involving a base equipped with a numberof support arms, from which an upright rises, composed of a gascylinder. The end of said gas cylinder, from which the activation buttonof the piston protrudes, is inserted inside a hole in the shape of atruncated cone, extracted monolithically from the containing boxstructure of the device.

[0014] More significant is U.S. Pat. No. 4,986,601 (Inoue), whichmentions the swinging mechanism to support a seat and the seat back of achair, consisting of a central column that extends from the base of thechair, a first support clamp connected to the central column by means ofa pedestal, a second support clamp connected to the chair and hinged tothe first support clamp by means of a shaft, a third support clampconnected to the rear support and hinged by means of a shaft to thesecond support clamp, and a shaft that hinges the first support clamp tothe third support clamp. U.S. Pat. No. 4,986,601 (Inoue) also providesfor a gas piston with a valve that can be actuated by a rod in thecentral column to selectively adjust the height of the column. Finally,U.S. Pat. No. 4,986,601 (Inoue) also provides for spring mechanisms toexert an opposing force on the second support clamp, positioned betweenthe first and second clamps.

[0015] DE0198056 (Neumuller) is of interest. This is a swingingmechanism to support the seat plane and the seat back of a chair,consisting of a central column that extends from the base of the chair,a first support clamp connected to the central column, a second supportclamp connected to the seat plane and pivoted to the first clamp by afirst pin, a third support clamp connected to the seat back and hingedto the second support clamp by a second pin, in addition to a mechanismthat pivots the first support clamp to the third support clamp.DE0198056 (Neumuller) also provides for spring mechanisms positionedbetween the first and second support clamps, to exert an opposing forceto the movement of the second clamp. DE0198056 (Neumuller) also providesfor locking mechanisms, consisting of a third pin connected to the firstclamp and a fourth pin connected to the second clamp, working togetherwith a number of disks equipped with an elongated slot through which thepin passes. A rod associated with the respective pin provides thefriction anchoring of the disks, which are thus held together.

[0016] U.S. Pat. No. 5,921,630 (Cassaday) is a conventional example ofhow the control devices for the various adjustment functions of the seatare typically positioned underneath the seat plane.

[0017] These traditional solutions may finally be complemented by otherswhich are less popular but more recent. In short, they can be understoodas providing for a button for locking/release the height of the seatplane, which is usually located along the side of the chair, appearingtowards the outside and at the side of the seat plane. In this case, thebutton, by means of a small cable integrated along the side of thechair, at the side of the seat plane, is brought close to the top of thegas column, where it interacts with an accessory enabling the heightadjustment device to be activated.

[0018] Ultimately, it is possible to state, in summary, that adjustmentdevices are known which include:

[0019] 1. a first lever arm, positioned underneath the seat plane, oneend of which constitutes the handle, while the other end, pivoted to thesupport structure of the seat plane, activates the height adjustmentdevice provided at the top of the small column;

[0020] 2. a second lever arm, always positioned underneath the seatplane, on the opposite side or the same side as the first, one end ofwhich constitutes the handle, while the other end is interconnected witha locking/release device for the swinging function or synchronizedmovement function of the seat and the seat back;

[0021] 3. a button, constituting an alternative to the first lever,positioned along the side of the seat plane, sometimes at the side ofthe body shell, which, by means of a small flexible cable, activates theheight adjustment device provided at the top of the small column.

PRIOR ART CONCERNING THE INVENTION

[0022] EP0329455 (Aero) proposes a device to adjust the inclination andlock the back of a chair. In more detailed terms, this is a push-buttondevice positioned along the external side and at the end of one of thetwo arms of an aircraft seat. Said button controls the running of acable arranged coaxially to a sheath, integrated into the arm andextending along the same towards the back until it reaches thetermination underneath the seat plane, where an actuator device ispositioned. Said actuator device is composed of a cylinder which, on oneside, provides the activation button stimulated by means of a set oflevers, from the small cable connected to the button and, from the otherside, activates, via the shaft, a movement arm controlled by the seatback.

[0023] U.S. Pat. No. 6,019,429 (Global) proposes a control device for achair for office use. In this specific case, it is a question of atleast one control button integrated into the arm of a chair, and morespecifically located directly underneath the support plane afforded bythe same arm, along the side and appearing towards the inside of theseat. In this hypothesis, the button is inserted coaxially to a support,consisting of a cylindrical guide body that can be implemented in thestructure of the arm. Even more specifically, said support provides forthe protrusion, on one side, of the button, which remains external withrespect to the arm, and on the other side (internally to the arm), bymeans of a fork arrangement, locks, with the lower part of the same, theend of the sheath, from which the respective control cable emerges. Theend of said control cable is implemented next to one end of anoverhanging lever with an “L” arrangement. This lever is in turnpivoted, sideways on, to the upper part of the fork, a little above thelower one. It usually consists of a pre-tensioned cable, which, by meansof the lever, ensures that the button always protrudes towards theoutside, enabling the user to activate the adjustment device by means ofexerting a light pressure on the same, in such a way as to cause theswinging of the lever in an upward direction, which thereforesubsequently pulls the control cable. To permit the activation of thecylinder, which in this case always controls the single function oflocking/releasing the back, the other end of the flexible cable alsouses a lever, which is pivoted, with a spring-back mechanism, at theside of the activation button located next to said movement cylinder ofthe back. In this way, with the button in the depressed position, thelever pivoted to the movement cylinder is brought considerably closer tothe base that holds the end of the sheath, with the result that, bymeans of a denticle, the latter exerts a force on the activation button,thus controlling the exit of the shaft.

DISADVANTAGES

[0024] In summary, both U.S. Pat. No. 4,986,601 (Inoue) and DE0198056(Neumuller), which provide for synchronized movements of the seat orseat back, possess a system of mechanical linkage, locking/release,positioned underneath the seat plane. Said device, conventionally usedboth for the inclination adjustment function of the seat plane and theseat back, and to preset the height of the seat, has the disadvantagethat is also shared by other solutions, such as U.S. Pat. No. 5,921,630(Cassaday), of particularly inconvenient access to the handles at theend of the respective adjustment levers. From the practical viewpoint,it is necessary that the user, after sitting down, must lean to eitherone side or the other, straining to stretch the arms to the area underthe seat containing the levers. Quite apart from the objectivedifficulty of identify it, due to the fact that, once seated, it isimpossible to locate it, since it is hidden by the seat plane above,there is the objective danger of accidents. The excessive free movementof the hands underneath the seat plane, intent on the usual searchingoperations, it can occur that the ends of the fingers can slip intoareas of the swinging device which are very dangerous. The presence ofarticulated arms, sharp areas, and mechanical parts in motion, which arenot adequately protected, is certainly one of the causes of frequentaccidents.

[0025] In EP0329455 (Aero) as in U.S. Pat. No. 6,019,429 (Global), themain disadvantage is associated with the position of the button. Indeed,in both the former and the latter, the position of the lock/releasebutton is along the side of the same armrest, and in one case along theexternal side, and in the other case along the internal side. However,both designs do not permit easy identification, which requires thefingers to touch the side of the armrest in an exploratory way so as tosearch for the respective control button. The inconvenient position ofthe fingers, during the searching, is also required due to the fact thatthe palm of the hand must always remain supported along the upper sideof the armrest, and in such a way as to exert the appropriate forcerequired to overcome the resistance of the button.

[0026] Another significant disadvantage, in the case of both EP0329455(Aero) and U.S. Pat. No. 6,019,429 (Global), is the fact that thecontrol button located along the armrest, since it has only a singlecontrol, is of the type capable of performing a dual function. In moredetail, each button illustrated has two positions, the first a restposition or static condition, which permits the locking of the seatplane or seat back in the desired position, and a second dynamic ordepressed position, during which, due to the fact that the buttonactivates the actuator device, it permits the inclination of the seatplane or seat back until it reaches the desired position, whereupon thebutton is finally released and the movement is therefore locked. Thefact of providing the single-control adjustment button may, from apractical viewpoint, confuse the user about the desired function, in thesense that the user, by pressing the button, is not capable of knowingexactly what function is activated at any given time. This feeling ofuncertainty persuades the user to preventively check the activatedfunction by means of the concomitant body movement, which consequentlyinvolves greater work for the structure, an excessive strain on thearticulations of the chair due to the fact that a normal force is notusually exerted, but rather one tends to increase the intensity ofapplication when it comes to performing a check.

[0027] Yet another disadvantage, applicable to both EP0329455 (Aero) andU.S. Pat. No. 6,019,429 (Global) concerns the fact that the buttons,positioned along the external or internal side of the armrest, areparticularly prone to accidental contact. In fact, it may happen that anunusual movement, for example of the legs or arm, may bump by chanceagainst the surface of the button, unexpectedly activating the releasefunction. Quite apart from the surprise or shock engendered in the user,the main disadvantage is an excessive strain on the structure andmechanical parts, which increases wear and tear even to the extent ofcausing the possible breakage of certain parts.

BRIEF SUMMARY OF THE INVENTION

[0028] This and other purposes are fulfilled by the present innovation,according to the characteristics of which in the annexed claims, itsolves the problems indicated above by means of a high-technologyarmrest with integrated buttons connected to a command transmissioncable for the adjustment of the seat and the seat back movements of anoffice chair with articulations for the synchronized movement of theseat plane and the seat back, comprising a mobile base of the “rocketlauncher” type, from which base a column rises, which is adjustable inheight, and which supports the seat plane and the reciprocally hingedseat back, whereby:

[0029] a first armrest of the office chair is equipped near the frontend with two side-by-side buttons, of which a first button performs thefunction of releasing the movement of the seat plan and the inclinationof the seat back, and a second button, adjacent to the first, activatesthe locking function of the seat plane and the inclination of the seatback;

[0030] a second armrest of the office chair, designed symmetrically tothe first, which is equipped near the front end with a single-controlbutton, for the function of adjusting the height of the chair.

PURPOSES

[0031] In this way, by means of the notable creative contribution, theeffect of which constitutes an immediate technological advance, certainobjectives are achieved, all substantially geared to permitting theoptimal use of the seat adjustment control devices integrated into thearmrests.

[0032] The principal purpose consists of improving the positioning ofthe control buttons. From a practical viewpoint, the fact of positioningthe buttons near to the edge, at the front end of the armrest, has themerit of preventing the same from being depressed accidentally, whichwould activate undesired and therefore unexpected functions.

[0033] A second purpose is that of making the buttons constantlyvisible. In this way, no effort is required of the user for the purposeof searching for the buttons along the armrest, which ultimately makesthe buttons readily available.

[0034] A third purpose concerns the fact of maximizing the ease ofreaching the position of the control buttons with the fingers of thehand in a normal position. This concerns achieving the greatestconvenience, and especially due to the fact that it is performedvertically, means that only a small force needs to be applied to thebuttons to cause the activation of the required function.

[0035] A fourth purpose is that of permitting the user to easilydistinguish between the desired functions, by dividing in two thelock/release command for the movement of the seat plane and theinclination of the seat back.

[0036] Finally, a further intended purpose is to permit the maintenancein a possible locked condition of the movement of the seat plane and theinclination of the seat back.

[0037] Ultimately, a seat structure can be created having with goodtechnological input, which integrates as many functions as possible,which can be offered to the public at a reasonably low cost.

[0038] This and other advantages will be discussed in the followingdetailed description of at least one preferential solution for theimplementation with the aid of the annexed schematic diagrams, thespecifics of the execution of which are not intended to be restrictive,but only exemplary.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0039]FIG. 1 is a view of the longitudinal section of the armrest, whichpossesses two buttons for the locking/release of the movement of theseat plane and the inclination of the seat back, shown in the restingcondition.

[0040]FIG. 2 is another view of the longitudinal section of the armrestof FIG. 1, with the locking button activated, which moves the retainingcog, which is not yet engaged.

[0041]FIG. 3 is another view of the longitudinal section of the armrestof FIG. 1, with the locking button activated, shown with the retainingcog in the engaged condition.

[0042]FIG. 4 is another view of the longitudinal section of the armrestof FIG. 1, with the release button activated, shown with the retainingcog in the disengaged condition.

[0043]FIG. 5 is an overhead view of the armrest which includes thelocking/release buttons for moving the seat plane and the inclination ofthe seat back;

[0044]FIG. 6 is a side view of the armrest in the preceding Figure;

[0045]FIG. 7 is a frontal view of the armrest in FIG. 5;

[0046]FIG. 8 is an overhead view of the armrest which includes thesingle-control button for adjusting the height of the chair;

[0047]FIG. 9 is a side view of the armrest in the preceding Figure;

[0048] finally, FIG. 10 is a frontal view of the armrest in FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

[0049] Taking the figures as a reference, it is observed that thestructure of an office chair is composed of a base that supports a seatplane and a seat back above, and these last two are reciprocallyimplemented, one on the other. Between the base and the articulatedassembly of the seat plane and the seat back above, there is a verticalcolumn, mostly composed of a gas cylinder, with a conventionalactivation button located near the upper end, which allows theadjustment of the height of the seat. Finally, as regards the structureof the chair, it is noted that under the corresponding seat plane thereis a locking/release device for the articulated assembly of the seatplane and the seat back above.

[0050] In more detail, along each of the two sides, on the right andleft sides respectively of the seat plane of the office chair, thererises a corresponding tubular upright, 1 and 2, slightly inclinedtowards the front part. The upper part of said upright, 1 and 2,incorporates an armrest 3 and 4, which possesses a sheathed staticsupport structure 5, substantially closed to wrap around the lower endpart of the corresponding tubular upright 1 and 2 and with a surfacedrawn along the upper side of the armrest 3 and 4, which functions as abase plane 6 for the respective forearm, essentially flat but slightlycurved. Said base plane 6 of each of the two armrests 3 and 4,possesses, next to the front side 60, a recess 61 inside of which ishoused at least one button 7, 8 or 9. In this case, while the buttons 7,8 provided next to the armrest 3 constitute the controls for locking 7and releasing 8 the swinging movement of the articulated assembly of theseat plane and the seat back, the single-control button 9, located onthe armrest 4, permits the height adjustment of the seat, whichcomprises the articulated assembly of the seat plane and the seat back.

[0051] In even more detail, the buttons 7 and 8 act at the end of twolevers 70 and 80, which are side by side and interdependent on eachother, both located inside the sheathing structure 5 of the armrest 3.Said levers 70 and 80 are, from the other side, pivoted with a pin 19towards the rear part of the armrest 3, thus permitting the swinging,controlled by the springs 17 and 18, of the only front part of thelevers 70 and 80. A first lever 70 acts to lock the swinging device ofthe articulated assembly of the seat plane and the seat back. This islocated behind one side of the stay rod 10, and the stay rod 10 iscomposed of a flat element which moves to and fro axially with respectto the tubular part of the upright 1 which supports the armrest 3. Thestay rod 10 is substantially composed of a metal strip with a series ofholes resembling buttonholes 101, 102 and 103 spaced out along it. Thefirst hole 101 has the function, by means of the fixation bar 11 oflinking the upper end of the stay rod 10, and simultaneously, via theguide hole 101, permits axial movement, linked in the course of thelength of the same. In addition, said fixation bar 11, passing rightthrough the stay rod 10 and used with the ends in the static supportstructure 5, constitutes at the same time the locking component for theend of the motion of the levers 70 and 80. In the case in question,these are supplied along the upper edge of a respective housing 701, 801inside of which the affected part of the stroke of the fixation bar 11is partially housed. In the part directly above the guide hole 101, asecond guide hole 102 is present, inside of which a cog 702 is inserted,drawn sideways and integral with the lever 70. Finally, the third hole103 above the hole 102 permits the use of a second fixation bar 12 whichserves the purpose of permitting the stay rod 10 to be kept in the axialguide.

[0052] Next to the base 100 of the stay rod 10 is the end of a flexiblecable 13 which, together with the respective sheath 130 is made to runinside the tubular upright 1. In the solution shown, the end of thesheath 130 is inserted near the entrance of the tubular upright 1 intothe armrest 3, in such a way that, inside the armrest, the singleflexible cable 13 is extended with the respective end.

[0053] At the back of the stay rod 10, still inside the armrest 3, thereis a space in the internal layout of the same armrest, whichaccommodates a lever 14. Said lever 14, which interacts with the stayrod 10, is pivoted in its lower part to a fixation pin 140, which is anintegral part of the static structure of the armrest, permitting theupper part to swing forwards and backwards. This movement is controlledby means of a guide hole 141 in an intermediate position, linked bymeans of a guide pin 15 to the static structure of the armrest. A spring16 is positioned behind the lever 14 and with the respective ends exertsa force on one side against the same lever 14, and on the other sideagainst the internal surface of the static structure of the armrest.Along the front profile of the lever 14, there is a cog 142, the shapeof which includes an inclined plane followed by a leveling table. In thecase in question, along the rear side of the stay rod 10 which facestowards the lever 14, there is a counter-shaped profile corresponding tothe cog 142, formed in such a way that the two opposing inclined planescan create a guide surface for the sliding movement, causing the lever14 to move backwards, and consequently, due to the spring-back effectproduced by the spring 16, to be pushed forwards again to intercept thelower cog that projects near the end 100.

[0054] As regards the upper part of the lever 14, it is shaped like aspout 143 with an undercut housing 144. The profile of the shape 143defines the route of the guide pin 800 drawn sideways to the lever 80and with which it interferes, consequently determining the movement ofthe lever 14. In more detail, by pressing the button 8 with the releasefunction, the respective guide pin 800 stress the spout-shaped profile143 of the lever 14, determining the movement of the part including theretaining cog 142 of the cog near the end 100 of the stay rod 10.

[0055] Both the lever 70 and the lever 80 possess a spring 17 and 18,each of which exerts a force with its own lower end along the upper sideof the corresponding lever 70, 80, while the upper end of each exerts aforce on the static support structure of the armrest 3. Both the lockingbutton 7 and the release button 8 are brought back into their restingposition, all the way down, by the abovementioned springs 17 and 18.

[0056] In operational terms, by pressing the locking button 7 connectedto the lever 70, the rotation of the same lever around the fulcrum 19occurs. Attached to the stay rod 10 is the end of the steel cable 13which activates the locking pin of the chair. When the locking button 7is pressed, an upward movement of the stay rod 10 occurs, which iscoupled with, and held in its stop position by, the retaining cog 142,14. In this way, the desired situation of traction of the steel cable 13is determined, even if the button 7 is released. This technical featuredetermines the function of automatic searching for the lock position,that is to say, the device automatically finds the lock without the usermaintaining pressure on the button 7. To obtain the release of themechanism, the adjacent button 8 is activated, which, by means of thecorresponding and connected lever 80, causes the rotation of theretaining cog 14, 142, until the release of the stay rod 10 is obtained.Once the stay rod 10 has been released, the retaining cog 14, 142 turnswith force towards the stay rod 10 as a result of the spring 16.

[0057] As regards the functioning of the button 9 integrated into thearmrest 4, it is noted that this acts on the command key of the gascylinder which adjusts the height of the support column of the chair.More specifically, the device is similar to that prescribed for thearmrest of type 3, with the difference that the button has a singlecontrol and the retaining cog 14, 142 is not present. Indeed, the devicein question does not need to be bistable, and therefore, when the button9 is pressed by means of the lever 90, the stay rod 10 is activated, towhich is connected the steel cable 13 which activates the valve of thegas cylinder by means of the appropriate device. By releasing the button9, the command to activate the gas cylinder by means of the cable 5 isnot requested, and therefore the desired position is determined.

I claim:
 1. Office chair with a high-technology armrest equipped withintegrated control buttons of the type connected to a commandtransmission cable, for the adjustment of the movements of at least theseat back, consisting of a mobile base of the “rocket launcher” type,from which rises a column of adjustable height that supports the seatplane and back reciprocally hinged, characterized in that provision ismade for a first armrest of the office chair, which is equipped near thefront end with a pair of side-by-side buttons, of which a first buttonis for the function of releasing the movement of the seat plane andinclining the seat back, and a second button, adjacent to the first, isfor activating the function of locking the seat plane and theinclination of the seat back.
 2. Office chair with high-technologyarmrest equipped with integrated control buttons, according to claim 1,characterized in that provision is made for a second armrest,symmetrical to the first, which is equipped near the front end with asingle-control button for the adjustment of the height of the chair. 3.Office chair with high-technology armrest equipped with integratedcontrol buttons, according to claims 1 and 2, characterized in that thecontrol buttons interact with at least one elastically retracted lever,pivoted in the rear part of the armrest structure. This lever, by meansof a guide pin, uses a stay rod, which moves longitudinally, said stayrod maintaining the anchorage of the end of a flexible cable.
 4. Officechair with high-technology armrest equipped with integrated controlbuttons, according to the preceding claims, characterized in thatprovision is made for a lever with a corresponding retaining cog, whichcouples with the stay rod and holds it in its stop position.
 5. Officechair with high-technology armrest with integrated buttons connected toa command transmission cable for the adjustment of the seat and the seatback movements, comprising a mobile base of the “rocket launcher” type,from which base a column rises, which is adjustable in height, and whichsupports the seat plane and the reciprocally hinged seat back, so as toexecute a synchronized movement, characterized in that provision is madefor: a first armrest of the office chair, which is equipped near thefront end with two side-by-side buttons, of which a first buttonperforms the function of releasing the movement of the seat plan and theinclination of the seat back, and a second button, adjacent to thefirst, activates the locking function of the seat plane and theinclination of the seat back; a second armrest of the office chair,designed symmetrically to the first, which is equipped near the frontend with a single-control button, for the function of adjusting theheight of the chair.
 6. Structure of office chair, according to thepreceding claims, characterized in that, near to each of the two sides,respectively to the left and right of the seat plane of the officechair, there rises a corresponding tubular upright, slightly inclinedtowards the front part, which, in the upper part of said upright,incorporates an armrest which possesses a sheathed static supportstructure, substantially closed to wrap around the lower end part of thecorresponding tubular upright, and with a surface drawn along the upperside of the armrest, which functions as a base plane for the respectiveforearm, said base plane of each of the two armrests possesses, near thefront side, a recess inside which at least one button is housed. 7.Structure of office chair, according to the preceding claims,characterized in that the stay rod of the armrest is axially mobile withrespect to the tubular upright above it, inside which is held the sheathand the respective flexible cable.
 8. Structure of the office chair,according to the preceding claims, characterized in that the stay rod isequipped with a series of aligned guide holes.
 9. Structure of theoffice chair, according to the preceding claims, characterized in thatthe lever that consists of the retaining cog possesses, in its upperpart, a profile shaped in such a way as to engage with the releaselever.